The primary advantage in the use of zero insertion force connectors, namely, minimizing loading of interfitting contacts during connection, takes on particularly great significance as the number of contacts simultaneously made increases to levels today seen with circuit components produced by very large scale integration (VLSI) techniques. In this sector, a VLSI device may present a twenty-by-twenty pin array, i.e., a total of four hundred pins, for simultaneous individual mating with collectively supported sockets. The loading forces attending such connection are, of course, cumulative of the force per mating contact pair and can readily amount to a level which may be unattainable for an assembler or not sustainable by support housings of the respective pins and sockets.
A further problem presented to the connector designer by VLSI is that of readily facilitating connection and disconnection and while minimizing the space in which such insertion connection and disconnection are to be effected. Customary practices in the art in larger environs are not applicable. In the above example of VLSI connection, the twenty-by-twenty pin array may be presented in a square of less than two inches per side. In such limited space, the use of such measure as translation of separate socket contact parts into engagement with a pin following positioning of the pin in residence between the parts is unlikely, as is use of such measure as translating a contact-making slide through the plane of a contact array. One known VLSI zero-insertion force practice looks, rather than to such customary measures, to the deformation of a socket upon a pin resident therein. Use is made, for example, of a ring loosely encircling the socket when exposed to refrigerant-produced temperatures. Following assembly, the ring is responsive to return to ambient temperatures and shrinks tightly upon the socket to effect electrical connection thereof to the pin. Resort to such exotic measure both evidences the difficulty of the problem presented by VLSI to the connector art and present costliness of approaches to solve the problem.